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  1. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Oh, and led is lit
  2. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Situation: BD139 disconnected 2 x 2N3055 disconnected P1 pot turned half way R12/C6 connected 10k link removed U3 still getting hot Black probe of DMM connected to neg of C1 U1 1 2V 2 5.6V 3 5.6V 4 0V 5 2.5V 6 11.2V 7 41V 8 0V U2 1 0V 2 0V 3 3.8V 4 0V 5 0V 6 40.2V 7 41V 8 0V U3 1 4V 2...
  3. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Yep, building to Rev 6 July '14
  4. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thanks so much Audioguru. That sounds encouraging. Yech! BD139 and output transistors disconnected, R12/C6 connected I am getting 40V on pin7 of U2 BUT I am also getting 40V on pin6 of U2 and when turning pot pin3 goes from 0 to 4.8V. So not quite there yet.
  5. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thanks Audioguru Currently R6/C12 reconnected and 10k resistor removed. If pin 7 of U2 is pushing 40V it only has to traverse C5 to reach D11 and if D11 is not blocking 40V only has to get through R16 to reach emitter of BD139. So the 40V at collector of BD139 is correct? I would hate to...
  6. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thanks Audioguru, something concrete to work on. Days of power outages and internet outages, thanks to Zuma. Been hunting down that 40V signal. I have found that the 40V runs from Emitter on BD139 through R16, down past R12/C6 (other side of R12/C6 about 14V) through D11, through C5 and to pin...
  7. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    2N3055's disconnected and 10k resistor installed. BD139 disconnected. I then measured the voltages on the 3 desoldered leads as I'm very afraid of blowing my remaining new BD139. Voltage on leads: ( Neg probe of DMM connected to C1) E 40.2V C 40.9V B 0V
  8. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thanks Audioguru The readings on the individual pins are measured with one probe connected to the negative of C1
  9. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Is BD139's E too high or is B too low? Just so I know where to start looking:rolleyes:
  10. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Black Smock: This build is about a highly modified version of the chinese product using the chinese pcb. We are pretty far down the rabbit hole, so I suggest it would be better to start your own project. And welcome to EP
  11. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    BD139 readings with 2 output transistors disconnected: E 11.3V C 41V B 1.7V B to E = 9.6V E to C = 5.8V B to C = 0.1V
  12. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Some good news. I replaced the Chinese P1 pot with a decent pot and Pin 3 of U2 now goes from 0 to 11V when P1 adjusted
  13. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    This is the BD139's I ordered: http://www.mantech.co.za/Stock.aspx?Query=35M6218+and Checked BD139 again and base to emitter voltage 9.6V. Is the 5V you are talking about Vebo on the datasheet. If so, then yeah, probably history. I have 1 more BD139 but I will now wait for the replacement caps...
  14. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Just seen I've made an ooopsie reading BD139 The corrected readings are: E 28V C 40V B 18V
  15. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Just to confirm: My BD139: With the legs facing down the connections from left to right: E C B
  16. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thanks a mil again Audioguru. Just 2 notes: "Pin 6 of U2 stays at 18V when P1 turned During this test the BD139 is disconnected from pin 6 and R12 and C6 are disconnected from the output and connected to pin 6 instead then the opamp U2 should have a gain of 1+ [R12/(R11+RV2)]= about 30V/11.2V...
  17. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thank you for your help Audioguru. We know that problem areas are pin 4 of U3 which should be -1.3V. I have also replaced Q3, the BC557, so I am hoping the problem lies with C2 or C3 (waiting for replacements) and pin 7 of U3 which voltage is too high. How are the other voltages on U2 and U3...
  18. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Have replaced D5, D6 and 2 x D7. 2 Resistors check out ok and 2 caps on order U2: 1. 0V 2. 14V 3. 0.1V 4. 0V 5. 0.1.V 6. 18V 7. 40V 8. 0V U3(overheating) 1. 4.4V 2. 3.2V 3. 2.9V 4. 3.8V 5. 4.4V 6. 4.2V 7. 30.6V 8. 0V If I remove U3 pin 4 of U3 goes to 0.01V. Cannot for the life of me get it...
  19. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    You wrote: The power supply output was 41V because one or both output transistors are shorted from collector to emitter. When I test them with DMM on continuity I don't get OL but 558 on both
  20. bushtech

    Chinese Hiland 0-30V/Audioguru PSU build (down the rabbit hole)

    Thanks Audioguru. So could I have damaged them with the analogue MM.? I think they push 9V. When I switch on the power supply, the light in series goes bright and off which is good. But then it starts with a dim erratic flickering which I can also see faintly on the onboard led. Does this...
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